AGM versus Wet Cell for a 2 battery system

[peteco]

Some of you now have extensive understanding and experience with AGM batteries. Could you please provide a basic primer for those trying to decide between wet cells and AGM. I realize this depends on the system. I ask this for a basic setup with no high power needs (microwave or AC). I presently have two 6-volt Deka wet cells that are 6 years old and have worked fine. I may need to replace in the next year. I am OK with maintaining the wet cells and corrosion has not been a major issue. But if the AGM provide much better performance then I am OK spending the extra money.

[booster]

Originally Posted by peteco

Some of you now have extensive understanding and experience with AGM batteries. Could you please provide a basic primer for those trying to decide between wet cells and AGM. I realize this depends on the system. I ask this for a basic setup with no high power needs (microwave or AC). I presently have two 6-volt Deka wet cells that are 6 years old and have worked fine. I may need to replace in the next year. I am OK with maintaining the wet cells and corrosion has not been a major issue. But if the AGM provide much better performance then I am OK spending the extra money.

Since you don't have high load needs, don't have a fast charging source, don't have corrosion, got decent life, and are OK with the needed maintenance with wet cells. I can think of just about no reason for you to spend the extra for AGM batteries.

[peteco]

Originally Posted by booster

Since you don't have high load needs, don't have a fast charging source, don't have corrosion, got decent life, and are OK with the needed maintenance with wet cells. I can think of just about no reason for you to spend the extra for AGM batteries.

Thanks. One thing not clear to me is: how much usable energy is available in wet cell vs AGM.

[booster]

Originally Posted by peteco

Thanks. One thing not clear to me is: how much usable energy is available in wet cell vs AGM.

They are going to be very close if you compare good batteries of both types. If you have two 6 volt GC2 it will be about 220ah. 12 volts gp 27 batteries will be in the 115 each range for the highest.

You can take both to 20% state of charge. AGMs seem to want a faster recharge, if taken deep, per Lifeline, so big charger is better. Wet cells are better with smaller chargers. If you do happen to take them dead, most say the GC2 wet cells handle it the best, as you can equalize them to regain capacity.

On edit--If you do have two GC2 six volts, and have more vertical space available, Trojan makes taller versions that are 240 and 260ah. We had a set of the 260ah ones for quite a while, and they were very good. I sold them at 5 years when we did the big AGM bank swap, and they tested just like when they were new.

[peteco]

Originally Posted by booster

They are going to be very close if you compare good batteries of both types. If you have two 6 volt GC2 it will be about 220ah. 12 volts gp 27 batteries will be in the 115 each range for the highest.

You can take both to 20% state of charge. AGMs seem to want a faster recharge, if taken deep, per Lifeline, so big charger is better. Wet cells are better with smaller chargers. If you do happen to take them dead, most say the GC2 wet cells handle it the best, as you can equalize them to regain capacity.

On edit--If you do have two GC2 six volts, and have more vertical space available, Trojan makes taller versions that are 240 and 260ah. We had a set of the 260ah ones for quite a while, and they were very good. I sold them at 5 years when we did the big AGM bank swap, and they tested just like when they were new.

Thanks. That's the kind of information I was looking for. I suppose I could have researched the internet and found this out, but it would have taken me a long time. I hope this info is useful to others with similar power needs.

[GeorgeRa]

AGM advantages and disadvantages:
1. Practically eliminated outgassing
2. No maintenance
3. Can be mounted in any upright or side-up positions

Flooded Lead:
1. Outgassing risk (1. oxygen + hydrogen = big boom, 2. Sulfuring acid mist from boiling electrolyte) but reduced in maintenance free ones, absolutely not recommended in living quarters or in spaces where possible ignition source exists
2. Low cost

They both have the same the basic lead sulfuring acid chemistry, in AGM batteries the electrolyte is Absorbed in the Glass fibers Mat. The simplest way to compare lead acid batteries is by weight for given specs, higher weight = more lead, better.